Expansible chamber motor



Dec. 24; 1929. E. G. GARTIN EXPANSIBLE CHAMBER MOTOR Filed June 29, 1921y $7 i Qii N fii Patented Dec. 24, 1929 arr STATES ELMER G. GARTEN, OFCLAREMOIE T, NEW HAMPSHIRE, ASSIGN'OR T SULLIVAN IIIA- CI-IENERYCOMIPANY, A CORPORATION OF MASSACHUSETTS EXPANSIBLE CHAIYIBER MOTORAppzication filed. June 29,

My invention relates to eXpansible chamber motors, and more particularlyto eX- pansible chamber motors of the valveless type.

An object of my invention is to provide an improved expansible chambermotor. Another object of my invention is to provide an improvedexpansible chamber motor of the valveless type, especially adapted foruse in rock drilling and for similar purposes. A further object of minvention is to provide an improved valveiess motor in which the lengthof the piston may be a minimum and the over-all length of the tool,together with its weight, materially reduced. A further object of myinvention is to provide an improved valveless percussive motor having avery short piston and yet preventing material loss of pressure fluid byreason of its passage to the exhaust in an unexpanded condition. Otherobjects of my invention will be apparent from the followingspecification and appended claims.

In the accompanying drawings I have shown for purposes of illustration,one embodiment which my invention may assume in practice.

In these drawings,

Fig. 1 is a view partially in elevation and partially in centrallongitudinal section through a percussive tool constructed according tothe illustrative form of my invention. V

Fig. 2' is a transverse section on the line 2-2 of Fig. 1.

Fig. 3 is a vertical transverse sectional view taken substantially online 33 of Fig. 1.

Fig. 4 is a detail transverse section taken on line 44 of Fig. 1.

For purposes of illustration I have shown my invention embodied in apercussive tool comprising a cylinder 1 having a bore 2 of uniformdiameter which cylinder is provided at opposite ends with head members 3and 4. In front of the head member 3 is arranged a chuck housing 5within which is disposed a chuck of usual form comprising a bushing 6having the usual straight lugs 6 thereon cooperating, as laterdescribed. with straight grooves formed in the piston in transmittingrotation to the drill steel 8 dis- 1921. Serial No. 481,425.

posed in the chuck. To the rear of the head 4 is mounted a combinedhandle and head member 9 and between this member and the head member 4is a member 10 whose function will later be explained.

\Vithin the cylinder bore 2, piston 11 is reciprocable, this pistonbeing provided with a reduced striking bar 12 which is cut away atopposite sides as indicated at 13 to cooperate with the exhaust groove14 and passage 15 formed in the head member 3. The piston 11 is providedin its main portion with a plurality of parallel, longitudinal,peripheral grooves 16, these grooves being spaced apart bylongitudinally extending relatively narrow ribs 17. Admission to thecylinder bore 2 is by way of a port 18 disposed approximately mid-way ofthe length of the cylinder and to this port fluid under pressure issupplied by way of a fluid supply passage 19. In the top of the cylinderbore there are formed a pair of by-pass passages and 21 respectively,which are in alinement with each other and with the port 18. It will benoted that as the piston reciprocates, the pas sages 16 serve to connectthe inlet port 18 by way of the by-passes 20 and 21 alternately with theopposite ends of the cylinder. It will be noted that an exhaust port 22is provided in such position as to be opened by the rear end of thepiston 11 when the latter is at the forward end of its stroke. Thecenter of this exhaust port is spaced approximately 90 from the centerof the inlet port, and a second exhaust port may be provided, asindicated at 22, at a diametrically opposite point in the cylinder. Thepiston is hollow as indicated at 24 and provided with a bushing 25having spiral lands formed thereon and cooperating with spiral grooves26 formed on the rifle bar 27 which projects through the head 4 into thecylinder. The rifle bar 27 is provided with a pawl carrier member 28which carries pawls 29 cooperating with the teeth 30 formed on theinterior periphery of the intermediate head member 10. The front end ofthe striking bar 12 is provided with straight grooves 31 cooperatingwith the straight lugs 6 on the bushing 6. It will be obvious that asthe piston recipro cates, the ratchet 28 will cooperate with the ratchetteeth 30 and so that the piston will be caused to partake of aunidirectional but intermittent rotation. For the purpose of providingcleansing fluid for the drill steel 8, which is hollow as indicated at32, I provide a pair of concentric air and water tubes secured in therear head member 9 of the cylinder. The water is supplied to the inneror water tube 33 from a water connection 34 in a well-known manner.Surrounding the water tube is an air tube 35 to which air is suppliedthrough a passage 36 which communicates at its forward end with the boreof the cylinder in the same transverse plane as the middle of the inletport 18 by way of a port 37. Referring to Fig. 2, it will be noted thatthe port 37 is so disposed that the various pockets 16 cannotcommunicate with it at the same time that they communicate either withthe inlet port 18 or with the exhaust port 22 and 22'.

The mode of operation of this device is as follows: Assuming the partsin the position shown in Figs. 1 and 2, it will be obvious that fluidpressure is being conducted from the inlet port 18 through the uppermostgroove 16 to the by-pass 21 and so to the rear end of the cylinder. Asthe piston 11 moves forward, cut-off will occur at the moment when therear end of the groove 16 passes the front end of the port 21.;Admission to the front end of the cylinder will begin at the moment whenthe front end of the groove 16 begins to communicate with the by-pass20. During the forward stroke of the piston, exhaust takes place throughthe cut-away portions of the striking bar 13 and passages 14!: and 15,until the front end of the solid portion of the striking bar 12 reachesthe head 3, which occurs before admission to the front end begins.Thereafter cushioning in the front end of the cylinder takes place. Atthe end of its forward stroke, exhaust takes place from the rear end ofthe cylinder by way of the exhaust port 22 and 22. It will be notedthat, the piston reciprocates axially, it is also undergoing a step bystep rotation, but it will be readily apparent that the fluid entrappedin the various grooves 16 will not be conducted to the exhaust ports 22,22 unexpected, for each of the grooves 16 passes over the port 37 and sosupplies a jetof cleansing fluid to the air tube before it g is intocommunication with the exhaust, and thereafter the fluid discharged toexhaust is not very much above atmospheric pressure.

From the foregoin description, it will be clear that I have provided a.valveless rock drill having a piston of much less length than is usualwith valveless rock drills having the same piston stroke and in whichall leakage or loss of fluid to the exhaust is avoided.

While 1 have in this application specifically described one form whichmy invention may assume in practice, it will be understood that thisform of the same is shown for purposes of illustration, and that theinvention may be embodied in various other forms without departing fromits spiritor the scope of the appended claims.

W hat I claim as new and desire to secure by Letters Patent is:

1. In a rock drill, a cylinder, a piston reciprocable therein onadmission of motive fluid thereto, means for imparting angular movementto said piston during reciprocation thereof, fluid supply anddistribution means for said cylinder including fluid conducting passagesformed in said piston, exhaust means for said cylinder with which saidfluid conducting passages are communicable during movements of saidpiston, and passage forming means traversed by said fluid conductingpassages upon angular movement of said piston for conducting live fluidto a drilled hole.

2; In a rock drill, a cylinder, a piston movable reciprecable therein onadmission of motive fluid thereto, means for imparting angular movementto said piston during reciprocation thereof, fluid supply anddistribution means for said cylinder including fluid conducting passagesformed in said piston, exhaust means for said cylinder with which saidfluid conducting passages are communicable during movements of saidpiston, and passage forming means traversed by said fluid conductingpassages prior to the communication of the latter with said exhaustmeans and upon angular movement of said piston for conducting live fluidto a drilled hole.

3. In a rock drill, a cylinder, a piston reciprocable therein onadmission of motive.

fluid thereto, means for imparting angular movement to said piston duingreciprocation thereof, fluid supply and distribution means for saidcylinder including fluid conducting grooves formed on the periphery ofsaid piston, exhaust means for said cylinoer traversed by said groovesduring movements of said piston, and passage forming means communicablewith said grooves during angular movement of said piston for conductinglive fluid to a drilled hole.

4. In a rock drill, a cylinder, a piston reciprocable therein onadmission of motive fluid thereto, means for imparting angular movementto said. piston during reciprocation thereof, fluid supply anddistribution means for said cylinder including fluid conducting groovesformed on the periphery of said piston, exhaust means for said cylindertraversed by said grooves during movements of said piston, and passageforming means communicable with said grooves prior to the communicationof the latter with said exhaust means and upon angular movement of saidpiston for conducting live fluid to a drilled hole.

5. In a rock drill, a cylinder, a piston reciprocable therein onadmission of motive fluid thereto, rotation means for said piston, fluidsupply and distribution means for said cylinder includingcircumferentially spaced fluid conducting grooves formed on theperiphery of said piston, exhaust means for said cylinder controlled bysaid piston and with which said grooves are communicable, and passageforming means with which said grooves are sequentially communicableduring rotation of said piston for conducting live fluid to a drilledhole.

6. In a rock drill, a cylinder, a piston reciprocable therein onadmission of motive fluid thereto, means for imparting angular movementto said piston during reciprocation thereof, fluid supply anddistribution means for said cylinder comprising a fluid inlet port andby-pass passages leading to the ends of the cylinder arranged inalinement longitudinally thereof, said piston having a series oflongitudinally extending peripheral fluid conducting grooves adaptedsuccessively to connect said inlet port and bypass passages, exhaustmeans spaced circumferentially from said inlet port and controlled bysaid piston, said grooves communicating successively with said exhaustmeans during angular movement of said piston, and a port in saidcylinder wall intermediate said inlet port and said exhaust means forconducting fluid from said grooves to the hollow drill steel.

7 In a rock drill, a cylinder, a piston reciprocable therein onadmission of motive fluid thereto and having a striking bar thereon,means for imparting angular movement to said piston during reciprocationthereof, fluid distribution means comprising an inlet port, and bypasspassages leading to the ends of the cylinder arranged in alinementlongitudinally of said cylinder, a piston having a series oflongitudinally extending peripheral fluid conducting grooves adapted tosuccesd sively connect said inlet port and by-pass passages, exhaustmeans comprising a port controlled by one end of said piston and spacedcircumferentially from said inlet port and exhaust means controlled bysaid striking bar, said grooves communicating successively with saidexhaust port during angular movement of said piston, and a port in saidcylinder wall intermediate said inlet port and said exhaust port forconducting fluid from said grooves to the hollow drill steel.

8. In a rock drill, a cylinder, a piston reciprocable therein onadmission of motive fluid thereto and having a striking bar thereon,means for imparting angular movement E to said piston duringreciprocation thereof,

means cooperating with said piston to eflect intermittent butunidirectional rotation thereof, fluid distribution means comprising aninlet port and by-pass passages leading to the ends of the cylinderarranged in alinement longitudinally of said cylinder, a piston having aseries of longitudinally extending peripheral fluid conducting groovesadapted to successively connect said inlet port and bypass passages,exhaust means comprising a port controlled by one end of said piston andspaced circui'nferentially from said inlet port, and exhaust meanscontrolled by said striking bar, said grooves communicating successivelywith said exhaust port during angular movement of said piston, and aport in said cylinder wall intermediate said inlet port and said exhaustport for conducting fluid from said grooves to the hollow drill steel.

9. In a rock drill, a cylinder, a piston reciprocable therein, means forrotating said piston during reciprocation thereof, fluid distributionmeans comprising an inlet port and fluid conducting means on theperiphery of said piston, exhaust means comprising a port in thecylinder wall, said port being disposed at a less distancelongitudinally from said inlet port than the length of said fluidconducting means, and means for supplying cleansing fluid to the drilledhole including a port communicating with said cylinder bore intermediatesaid inlet port and said exhaust port.

10. In a rock drill, a cylinder having a pressure fluid supply passagecommunicating therewith and an exhaust passage, a piston reciprocable insaid cylinder adapted to actuate a hollow drill steel having acircumferentially spaced longitudinally extending fluid conductinggrooves formed therein, means for imparting angular movement to saidpiston during reciprocation thereof, a cleansing fluid supply passagecommunicating with said hollow drill steel, and means to successivelyconnect one of said grooves with said supply passage, said cleansingfluid supply passage, and said exhaust passage during movements of saidpiston.

11. In a rock drill, a cylinder having a pressure fluid supply passagecommunicating therewith and exhaust means, a piston reciprocable thereinadapted to actuate a hollow drill steel, spaced fluid conducting groovesformed in said piston, a passage adapted to supply pressure fluid to thehollow drill steel, and means to rotate said piston to cause one of saidgrooves to successively communicate with said pressure fluid supplypassage, said passage adapted to supply pressure fluid to the hollowdrill steel and said exhaust means during movements of said piston.

12. In a rock drill, a cylinder having a pressure fluid supply passagecommunicating therewith and an exhaust, a piston reciprocable thereinadapted to actuate a hollow drill steel, circumferentially spaced fluidconducting grooves formed in said piston, a passage adapted to supplypressure fluid to the hollow drill steel disposed in the same plane assaid pressure fluid supply passage, and means to rotate said piston tocause one of said grooves to successively communicate with said pressurefluid supply passage and said passage adapted to supply pressure fluidto the hollow drill steel and said exhaust.

13. In a rock drill, a cylinder having a pressure fluid supply portcommunicating therewith and an exhaust, a piston reciprocable in saidcylinder adapted to actuate a hollow drill steel, circumferentiallyspaced longitudinally extending fluid conducting grooves formed in saidpiston, a cleansing fluid supply passage communicating with saidcylinder and extending to said hollow drill steel and means tointermittently rotate said piston to successively connect said grooveswith said supply port, said cleansing fluid supply passage and saidexhaust.

14. In a rock drill, a cylinder, a piston reciprocable therein onadmission of motive fluid thereto, means for imparting angular movementto said piston during reciprocation thereof, fluid supply anddistribution means for said cylinder includin a plurality of fluidreceiving pockets formed in said piston, exhaust means for said cylinderwith which said pockets are communicable, and passage forming meanstraversed by said pockets during angular movements of said piston forconducting intermittent blasts of live fluid to a drilled hole.

15. In a rock drill, a cylinder, a piston-reciprocable therein onadmission of motive fluid thereto, means for'imparting angular movementto said piston during reciprocation thereof, fluid supply anddistribution means for said cylinder including a plurality of fluidreceiving pockets formed in said piston, 4

exhaust means for said cylinder with which said pockets arecommunicable, and passage forming means traversed by said pockets priorto the communication of the latter with said exhaust means and duringangular movement of said piston for conducting intermittent blasts oflive fluid to a drilled hole.

16. In a rock drill, a cylinder, a piston reciprocable therein onadmission of motive fluid thereto, means for imparting angular movementto said piston during reciprocation thereof, fluid supply anddistribution means for said cylinder including fluid conducting passagesformed in said piston, exhaust means for said cylinder with which saidfluid conducting passages are communicable during movements of saidpiston, and passage forming means with which said fluid conductingpassages are sequentially communicable during angular movement of saidpiston for conducting intermittent blasts of live fluid to a drilledhole.

17. In a r ck drill, a cylinder, a piston reciprocable therein onadmission of motive fluid tiereto, means for imparting angular movementto said piston during reciproca tion thereof, fluid supply anddistribution means for said cylinder including circumferentially spacedlongitudinally extending fluid conducting grooves formed on theperiphery of said piston, exhaust means for said cylinder with whichsaid grooves are communicable during angular movements of said piston,and passage forming means with which said grooves are sequentiallycommunicable during angular movement of said piston forconductingintermittent blasts of live fluid to a drilled hole.

In testimony whereof I aflix my signature.

ELMER G. GABTIN.

CERTIFICATE OF CORRECTION.

Patent No. 1,740,685. Granted December 24, 1929, to

ELMER G. GARTIN.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,line 51, for the word "unexpected" read "unexpanded", and lines 88 and89, claim 2, strike out the word movable"; page 3. line 98, claim 10,strike out the article "a" second occurrence; page 4, line 3, claim 12.strike out the word "and" and insert a comma; and that the said LettersPatent should be read with these corrections therein that the same mayconform to the record of the case in the Patent Office.

Signed and sealed this 13th day of May, A. D. 1930.

M. J. Moore, (Seal) Acting Commissioner of Patents.

